IT HAS taken the best part of two seasons, but cracks are finally starting to show in the Special One's veneer. Saturday's 3-0 defeat to Middlesbrough could be written off as an individual aberration were it not for a gradual deterioration that has been apparent in Chelsea's play for the last couple of months.

Everything is relative, of course, and the Blues are still head and shoulders above any other team in the country.

They will win the Premiership, probably by a record margin, and could yet complete the double by also lifting the FA Cup. They are not invincible, though, and, since Christmas, have lost some of the untouchable aura that made them such feared opponents on the domestic stage.

They have also mislaid much of the style and swagger that threatened to make them champions on the continent and, unless they rediscover their finest form quickly, the forthcoming Champions League clash with Barcelona will provide a painful jolt to the system.

In part, the undoubted dip in Chelsea's form is an unavoidable consequence of their dominance of the English game.

Mourinho's men could afford to lose by three goals at the Riverside and still boast a 12-point lead over their closest rivals, Manchester United.

With such a sizeable cushion, it is little surprise that Chelsea's players have struggled to perform to their peak in league games against the likes of Middlesbrough, Everton and Charlton. Perhaps if Manchester United can whittle their lead down to single figures, the champions will rediscover the hunger that enabled them to amass win after win at the start of the season.

Perhaps even that would fail to produce an instant response though because while Chelsea's invincibility has hampered them in recent weeks, there are other factors underpinning their downturn in form.

And, while it might be best to whisper it in his presence, some of those factors begin and end with Mourinho.

Having finally lost patience with errant Spaniard Asier Del Horno - one of his few failures in the transfer market - the former Porto boss played William Gallas at left back at the weekend.

With Paulo Ferreira injured, that meant he had to field Geremi as a makeshift full-back on the opposite flank and, while the former Middlesbrough midfielder made a decent fist of handling the lively Stewart Downing, his removal at half-time underlined just how unsuccessful the policy had been.

Things got worse, of course, when Gallas had to be withdrawn himself midway through the first half. Chelsea have a ready-made replacement in Wayne Bridge - the only problem is that the England international was more than 200 miles away playing for Fulham.

Given Del Horno's well-publicised problems, Mourinho's decision to allow Bridge to leave on loan will start to look very foolish indeed if Gallas is sidelined for any significant period of time.

To compound the situation even further, Chelsea's defence is suffering from Ricardo Carvalho's complete lack of confidence.

The Portugal international was an accident waiting to happen on Saturday, with his mistimed challenge for Aiyegbeni Yakubu's third goal providing a fitting summation of a thoroughly wretched display.

Mourinho has been rightly lauded for his handling of his Chelsea players.

A mixture of carrot and stick has converted Joe Cole from show pony to thoroughbred, while even the temperamental Hernon Crespo appears happy with his lot at Stamford Bridge.

But, at the start of the season, Carvalho became one of the few players to have felt the wrath of Mourinho's tongue when he was publicly admonished for questioning his bit-part role in the opening month of the campaign.

His form dipped immediately and, despite his manager claiming the matter was forgotten, it is yet to recover. While criticising Mourinho is akin to heresy, perhaps he might have been better served expressing his displeasure behind closed doors.

With Saturday's defeat meaning little in the grand scheme of things, it may seem churlish to question the methods of a manager who is about to win his second successive Premiership title.

Mourinho leaves himself open to such questioning, though, as his entire modus operandi revolves around being the best.

He remains the leading manager in the country and his side remains the ideal to which all domestic challengers aspire but, in the last few months, he has been shown to have his flaws.

While his reputation as the Special One remains intact, he is not immune to making the odd mistake.